• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.347-351
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• 2004

[ $Si_3N_4$ ] composites have been extensively studied for engineering ceramics, because it has excellent room and high temperature strength, wear resistance properties, good resistance to oxidation, and good thermal and chemical stability. In the present work, carbon short fiber reinforced $Si_3N_4$ ceramics were fabricated by hot press method in $N_2$ atmosphere at $1800^{\circ}C$ using $Al_2O_3\;and\;Y_2O_3$ as sintering additives. Content of carbon short fiber was $0\%,\;0.1\%\;and\;0.3\%$. The composites were evaluated in terms of density, flexural strength and elastic modulus through the 3-point bending test at room temperature. Also, The wear behavior was determined by the pin on disk wear tester using silicon nitride ball. Experimental density and flexural strength decreased with increasing content of carbon fiber. But specific modulus increased with increasing content of carbon fiber. In addition, friction coefficient and specific wear loss decreased with increasing content of carbon short fiber by reason of interfacial defects between matrix and fiber.

• 대한전자공학회논문지SD
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• 제40권5호
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• pp.290-297
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• 2003

전자와 정공의 온도 관련 이온화 계수로부터 추출한 온도 함수의 유효 이온화 계수 및 전자 이동도를 이용하여 실리콘 전력 MOSFET의 항복 전압과 on 저항을 위한 온도 함수의 해석적 표현식을 유도하였다. 온도 함수의 해석적 항복 전압 결과를 4x10/sup 14/ cm/sup -3/, 1x10/sup 15/ cm/sup -3/, 6x10/sup 16/ cm/sup -3/의 도핑 농도에 대해 각각 실험 결과와 비교하였고, 온도 및 항복 전압 함수의 on 저항 변화도 각각 실험 결과와 비교하였다. 각농도에 따른 온도 함수의 해석적 항복 전압은 77∼300k의 온도 범위에서 실험 결과와 10% 이내의 오차로 잘 일치하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 추계 학술논문 발표대회
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• pp.148-149
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• 2016

In this paper, the increase in chloride resistance of footing concrete at coastal area was evaluated by replacement of Mineral Admixture. In KBC 2009, the footing concrete's minimum specific concrete strength at coastal area is determined to 35MPa. However, this is criteria only based on the strength aspect. Thus, it is not considered to increase the chloride resistance by replacement of Mineral Admixture. According to the test results of chloride ions penetration resistance, 35MPa class concrete with OPC 100% shown inaccessible state. Low-strength (24~30MPa class) concretes with Mineral Admixture, however, presented better performances. In addition, chloride diffusion coefficient tests showed identical appearance. Therefore, the current KBC's chloride resistance criteria based on only concrete strength has to review for the reason it can cause many problems (ex. cost increases by growing concrete strength and the environmental issues by a lot of cement use).

• 한국정보시스템학회지:정보시스템연구
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• 제28권3호
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• pp.159-202
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• 2019

Purpose The purpose of this study is to explain users' wearable healthcare device adoption using performance expectancy, effort expectancy, the hedonic motivation and price value of UTAUT2, and to identify the causal relationship between intention to use wearable healthcare device and innovation resistance formed by perceived risks. Design/methodology/approach The research model proposed in this study is based on UTAUT2(Extended Unified Theory of Acceptance and Use of Technology) and MIR(Model of Innovation Resistance). In specific, performance expectancy, effort expectancy, hedonic motivation and price value of UTAUT2 and innovation resistance formed by perceived risks of MIR are adopted in our research model. To validate the research model, we carry out the analysis of the survey data using Smart PLS 3.0 to test the hypotheses. Findings According to the empirical analysis results, this study confirms that the performance expectancy, effort expectancy, hedonic motivation, and price value have significant effects on the intention to use wearable healthcare devices. It also finds that perceived risk affects innovation resistance and in turn, innovation resistance affects the intention to use wearable healthcare devices.

• 운동영양학회지
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• 제14권2호
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• pp.75-80
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• 2010

We evaluated the effect of the ginsenoside Re on insulin resistance of glucose transport in muscles of rats made insulin resistant with a high fat diet. After a week of adaptation period to the laboratory environment, 40 male wistar rats were randomly assigned into 2 groups (Chow diet group; CD, n = 20, High fat diet group; HFD, n = 20). After 5-week of high fat diet, Food was removed after 6:00 PM the day before the experiment. The following morning, rats were anesthetized by an intraperitoneal injection of pentobarbital sodium (50 mg/kg body wt), and the soleus muscles were removed. Before incubation, the soleus muscle was split longitudinally into strips with an average weight of 15~20 mg. After the muscle dissection was completed, the abdominal cavity was opened, and the epididymal, mesenteric, and retroperitoneal fat pads were removed and weighed. Treatment of muscles with ginsenoside Re alone had no effect on glucose transport. The high fat diet resulted in ~50% decreases glucose transport rate in soleus muscles. Treatment of muscles with ginsenoside Re in vitro for 90 min completely reversed the high fat diet-induced insulin resistance of glucose transport in soleus muscles. This effect of ginsenoside Re is specific for insulin stimulated glucose transport, as Re treatment did not reverse the high fat diet-induced resistance of skeletal muscle glucose transport to stimulation by contraction. Our results show that the ginsenoside Re induces a remarkably rapid reversal of high fat diet-induced insulin resistance of muscle glucose transport.

• Weed & Turfgrass Science
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• 제6권1호
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• pp.28-31
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• 2017

The mutation rate of proline in the position 197 (Pro197) in acetohydroxy acid synthase (AHAS) is highest among sulfonylurea (SU) herbicide-resistance mutants. Therefore, it is significant to investigate the resistance mechanism for the mutation and to develop the herbicides specific to the mutants. SU herbicide resistance mechanism of the mutants, 197Ser, 197Thr and 197Ala, in AHAS were targeted for designing new SU-herbicide. We did molecular dynamics (MD) simulation for understanding SU herbicide-resistance mechanisms of AHAS mutants and designed new herbicides with docking and MD evaluations. We have found that mutation to 197Ala and 197Ser enlarged the entrance of the active site, while 197Thr contracted. Map of the root mean square derivation (RMSD) and radius gyrations (Rg) revealed the domain indicating the conformations for herbicide resistant. Based on the enlarging-contracting mechanism of active site entrance, we designed new herbicides with substitution at the heterocyclic moiety of a SU herbicide for the complementary binding to the changed active site entrances of mutants, and designed new herbicides. We confirmed that our screened new herbicides bonded to both AHAS wild type and mutants with higher affinity, showing more stable binding conformation than the existing herbicides.

• The Plant Pathology Journal
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• 제20권1호
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• pp.46-51
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• 2004

Host resistance is usually parasite-specific and is restricted to a particular pathogen races, and commonly is expressed against specific pathogen genotypes. In contrast, resistance shown by an entire plant species to a species of pathogen is known as non-host resistance. Therefore, non-host resistance is the more common and broad form of disease resistance exhibited by plants. As a first step to understand the mechanism of non-host plant defense, expressed sequence tags (EST) were generated from a hot pepper leaf cDNA library constructed from combined leaves collected at different time points after inoculation with non-host soybean pustule pathogen (Xanthomonas axonopodis pv. Glycines; Xag). To increase gene diversity, ESTs were also generated from cDNA libraries constructed from anthers and flower buds. Among a total of 10,061 ESTs, 8,525 were of sufficient quality to analyze further. Clustering analysis revealed that 55 ％ of all ESTs (4685) occurred only once. BLASTX analysis revealed that 74％ of the ESTs had significant sequence similarity to known proteins present in the NCBI nr database. In addition, 1,265 ESTs were tentatively identified as being full-length cDNAs. Functional classification of the ESTs derived from pathogen-infected pepper leaves revealed that about 25％ were disease- or defense-related genes. Furthermore, 323 (7％) ESTs were tentatively identified as being unique to hot pepper. This study represents the first analysis of sequence data from the hot pepper plant species. Although we focused on genes related to the plant defense response, our data will be useful for future comparative studies.

• The Plant Pathology Journal
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• 제38권6호
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• pp.629-636
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• 2022

Colletotrichum species is known as the major causal pathogen of red pepper anthracnose in Korea and various groups of fungicides are registered for the management of the disease. However, the consistent use of fungicides has resulted in the development of resistance in many red pepper-growing areas of Korea. Effective management of the occurrence of fungicide resistance depends on constant monitoring and early detection. Thus, in this study, various methods such as agar dilution method (ADM), gene sequencing, allele-specific polymerase chain reaction (PCR), and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) were applied for the detection of benzimidazole resistance among 24 isolates of Colletotrichum acutatum s. lat. and Colletotrichum gloeosporioides s. lat. The result of the ADM showed that C. gloeosporioides s. lat. was classified into sensitive and resistant isolates to benomyl while C. acutatum s. lat. was insensitive at ≥1 ㎍/ml of benomyl. The sequence analysis of the β-tubulin gene showed the presence of a single nucleotide mutation at the 198th amino acid position of five isolates (16CACY14, 16CAYY19, 15HN5, 15KJ1, and 16CAYY7) of C. gloeosporioides s. lat. Allele-specific PCR and PCR-RFLP were used to detect point mutation at 198th amino acid position and this was done within a day unlike ADM which usually takes more than one week and thus saving time and resources that are essential in the fungicide resistance management in the field. Therefore, the molecular techniques established in this study can warrant early detection of benzimidazole fungicide resistance for the adoption of management strategies that can prevent yield losses among farmers.

• 전기전자학회논문지
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• 제26권4호
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• pp.728-735
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• 2022

이번 연구에서 우리는 낮은 온 저항을 위해 p-well 영역 아래에 도입된 전류 확산층을 변화시켜 고전압 4H-SiC 전력 Diffused MOSFET(DMOSFET)에 대해 연구했다. Current Spreading Layer(CSL)의 두께(T_CSL)를 0~0.9 um, CSL의 도핑 농도(N_CSL)를 1~5×10¹⁶ cm^-3으로 변화시키면서 소자의 전기적 특성을 분석하였다. TCAD 2D-simulation을 통해 최적화되었으며 CSL이 온 저항을 낮추는 것뿐만 아니라 항복전압도 낮춤으로써 CSL의 최적화의 중요성을 확인하였다. 최적화된 구조는 59.61 mΩ·cm²의 온저항, 5 kV의 항복전압, 0.43 GW/cm²의 Baliga's Figure of Merit(BFOM)을 보여주었다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.389-393
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• 2007

The most demanded bimetals in home appliances are manufactured by mainly cladding process and these are mainly consist of Cu alloy and Ni alloy. But it is very difficult to clad these alloys, because the brittle ${Cu_3}{O_4}$ oxide film formed easily on Cu alloy surface during cladding process. Clad rolling and heat treatment processes were applied for the development of bimetals by using the Ni alloy and the 3 types of Cu alloys. Optical microstructure was observed and micro-hardness, specific resistance, deflection were measured from the manufactured new bimetals specimens.